1. Field of the Invention
The present invention relates to imprinting apparatuses that transfer the pattern of a mold to a resin layer and imprinting methods therefor.
2. Description of the Related Art
An ultrafine processing technology for transferring a microstructure on a mold onto a workpiece made of resin, metal, etc. has recently been developed and attracts attention (Stephan Y. Chou et al., Appl. Phys. Lett, vol. 67, issue 21, pp. 3114-3116 (1995)). This technology is referred to as nanoimprinting or nanoembossing and provides a resolution of the order of a few nanometers, and therefore, it is increasingly expected as the next-generation semiconductor manufacturing technology that replaces photolithography machines, such as steppers and scanners. Furthermore, since the technology can collectively process a three-dimensional structure at wafer level, applications to broad fields are expected as a technology for manufacturing optical elements, such as photonic crystal, and biochips of a micro total analysis system (μ-TAS) etc.
Such a processing technology is performed as follows when applied to a semiconductor manufacturing technology, for example. A work having a photo-curable resin layer on a substrate (for example, a semiconductor wafer) and a mold having a desired embossed pattern are put together, with the resin layer therebetween, the mold is pressed onto the resin, and the resin is irradiated with ultraviolet rays to cure the resin. Thus, the pattern is transferred to the resin layer. This resin layer is used as a mask layer for etching etc. to form the pattern on the substrate.
In such imprinting, U.S. Pat. No. 7,077,992 discloses a step-and-repeat method for transferring the pattern onto a substrate one by one using a mold smaller than the substrate is known as a method suitable for a semiconductor manufacturing process. This method can decrease integration errors when drawing a mold pattern with increases in size and can reduce mold manufacturing costs by setting the mold size smaller than the substrate size.
As a method suitable for forming a resin layer by the step-and-repeat method, U.S. Patent Application Publication. No. 2005/0,270,312 discloses a drop-on-demand method for depositing resin every shot. This method can make the thickness of an imprinted resin layer uniform by locally adjusting the amount of resin in accordance with the density and shape of the mold pattern, thereby improving the transfer accuracy.
However, for application to the semiconductor manufacturing technology described above it is necessary to improve the throughput. In particular, it is pointed out that the process of pressing the mold onto the resin on the substrate takes very much time. Furthermore, it is also pointed out that the process of depositing resin every shot by the drop-on-demand method takes very much time.
Thus, U.S. Patent Application Publication No. 2007/0,102,838 discloses a method for performing the process of pressing the mold onto the resin and the process of depositing the resin at the same time using two substrate stages and a method for using two resin depositing units.
However, since manufacture of substrate stages costs more than that of other mechanisms, the apparatus having two substrate stages, as in U.S. Patent Application Publication No. 2007/0,102,838, has the issue of increasing the cost. The method of using two resin depositing units deposits resin only while the substrate stage moves, in which the process of pressing the mold onto the resin and the process of depositing the resin are performed at different times. Therefore, this may have not so good effect for high throughput.